This invention relates to swimming pools and more particularly to swimming pool drains that are designed to prevent entrapment while accommodating high water flow volume that may be encountered in modern swimming pools. Pool water circulating systems circulate and filter significant quantities of water; water is removed from the main drains and delivered to filtering systems and subsequently reintroduced into the pool. Various pool systems have incorporated many variations on this circulation system; however, several problems have persisted. The problem of limb and hair entrapment has become increasingly important especially with the advent of greater flow volume resulting from the frequent need to supplement the pool recirculation system with added water features such as water fountains or spas.
Prior art pool designs have frequently attempted to overcome these difficulties by the incorporation of multiple drains; that is, a single pool main drain is replaced by two or more drains separated by a predetermined minimum distance. In this manner, a swimmer coming in contact with one of the drains and creating what otherwise would be a serious or fatal drain contact, will merely cause the flow rate through the remaining or uncovered drain to increase. The swimmer would thus be able to release themselves from contact with the main drain. The inclusion of multiple drains, however, incorporates significant additional costs in the manufacture of a pool and particularly increases the cost of pool installation.
The addition of supplemental water features such as spas and the like significantly contribute to the difficulty encountered with the use of single drains. The added requirement for water flow volume caused by the added features increases the flow volume through the drain thus significantly increase the difficulties concerning entrapment.